The present invention generally relates to the field of spectroscopy, and more particularly, to an underwater spectroscopic detector for detecting substances in aqueous solutions.
Current Navy practices for detecting petroleum spills at marine facilities rely solely upon human visual observation to identify the surface sheen caused by oil floating on water. The problem with the practice is that visual observation provides only a limited and often unreliable means of detecting spilled fuel or oil. Many spills occur at places or times in which no one is present to discover the event. Even when an observer is present, visual spill sighting is difficult during foul weather and is completely ineffective at night. Prompt containment of oil spills is important in order to minimize the difficulty and environmental damage caused by such spills. Therefore, a need exists for a reliable system that can promptly detect an oil spill.
One type of oil spill detector employs fluorometric sensors mounted above the water surface on a free floating buoy platform. When an oil spill is detected, the sensors generate a signal that triggers an alarm. Because the detector floats on the surface of the marine environment, the optical energy generator used to stimulate fluorescent of the oil particles and the attendant electronics are encased in an explosion proof housing to eliminate the risk of explosion that would occur if explosive volatile components, such as are found in oil, should ever penetrate the detector. However, explosion proof housings are expensive and heavy. Further, this type of detector can detect surface contaminants, but not dissolved or emulsified petroleum products.
A problem with present underwater instruments in general is that optical elements exposed to marine environments tend to become fouled with biological organisms within mere days of deployment. Continued service of such detectors requires that they be periodically cleaned, an expensive and time consuming process which renders them unsuitable for extended deployments particularly in remote locations.
Therefore, a need exists for an oil spill sensor that avoids the risk of explosion and eliminates the need for an explosion proof housing. A need also exists for a detector that can detect contaminants within a water column, as well as on the surface of an aquatic body. A further need exists for an oil spill sensor that can be operated underwater for extended periods without becoming fouled with biological organisms.